1. Field of the Invention
The present invention relates to a liquid crystal display panel, and more particularly to a liquid crystal display panel with marks for checking cutting precision by visual inspection.
2. Description of the Prior Art
Since liquid crystal display devices provide advantages of low power consumption and easily carrying etc., the liquid crystal display devices are increasingly popular. The liquid crystal display device generally includes two components of a liquid crystal display panel and a backlight module. The liquid crystal display panel mainly includes a bottom substrate, a top substrate and a liquid crystal material filled between the bottom substrate and the top substrate. The bottom substrate has a plurality of thin film transistors formed thereon, which is called “array substrate” hereinafter, and the top substrate has a color filter plate formed thereon, which is called “color filter substrate” hereinafter. The liquid crystal display panel utilizes the properties of optical anisotropy and polarization of the liquid crystal material to display images. Due to the high resolution and the superiority of displaying dynamic images of the active matrix liquid crystal display panel, it becomes one of the most popular products.
A plurality of gate lines for receiving scanning signals and a plurality of data lines for receiving data signals are formed on the array substrate to define a plurality of pixel areas. A pixel electrode connected to one of the thin film transistors is formed on each of the pixel areas to apply a voltage to the liquid crystal material. The color filter plate of the color filter substrate corresponds to the pixel areas. The color filter plate includes a plurality of red, green and blue sub-filters. A black matrix is formed on the color filter plate to interrupt the light outside the region of the pixel electrodes to prevent the light from illuminating on the thin film transistors. The color filter substrate further includes a common electrode for applying the voltage to the liquid crystal material.
The common electrode and the pixel electrodes are respectively formed on the opposite inner surfaces of the color filter substrate and the array substrate. The liquid crystal material is filled between a space contained between the opposite inner surfaces of the color filter substrate and the array substrate. A polarizing film is respectively formed on the outer surfaces of the color filter substrate and the array substrate to complete the manufacture of the liquid crystal cells. The light transmissibility of the liquid crystal cells is controlled by the voltage applied on the common electrode and the pixel electrodes. Hence, the images can be displayed by a light-shutter effect.
FIG. 1 is a schematic cross-sectional view of an electronic device 1 having a capability of displaying. The electronic device 1 is disposed in a housing 2 and provided with a liquid crystal display device for displaying. For simplicity of the drawing, only the major components of the liquid crystal display device including a backlight light source and a liquid crystal display panel are shown in the drawing of FIG. 1. The liquid crystal display panel includes two transparent substrates 3 and 4 and a pair of sealing elements 5 and a liquid crystal material 6 filled between the two transparent substrates 3 and 4. The backlight light source is disposed under the liquid crystal display panel. The backlight light source comprises a backlight plate 2 and a lamp 8. The liquid crystal display panel is disposed on a printed circuit board 9, and the backlight light source is disposed under the printed circuit board 9. The printed circuit board 9 has an opening 10 for the light of the backlight light source passing through to enter the liquid crystal display panel. The housing 2 has an opening 11 corresponds to a display area of the liquid crystal display panel.
One of the key steps for assembling the components of the electronic device 1 is the mechanical alignment for assembling the liquid crystal display device in the housing 2. When the accuracy of the mechanical alignment for assembling the liquid crystal display device in the housing 2 can not be attained, the liquid crystal display device would be easily detached from the housing 2. In order to attain the accuracy of the mechanical alignment for assembling the liquid crystal display device in the housing 2, generally a mark is formed on an intersection of each pair of adjacent cutting lines of the liquid crystal display panel in order to check cutting precision of the liquid crystal display panel after completing the cutting of the liquid crystal display panel. FIG. 2 is a schematic plane view of a liquid crystal display panel before cutting, a liquid crystal display panel 21 is previously formed on a large substrate 20. A cutting line 22 is formed on each boundary of the liquid crystal display panel 21, and a cross mark 23 is formed on the intersection of each pair of the adjacent cutting lines 22. FIG. 2A is a partial enlarged view of FIG. 2, after completing the cutting of the liquid crystal display panel 21, the cutting precision of the liquid crystal display panel 21 is checked by measuring distances d1 and d2 between the cutting lines 22 and the cross mark 23. The measurement of the distances d1 and d2 take time. Thus, it takes longer time to check the cutting precision of the liquid crystal display panel 21 employing the cross mark 23. In order to save the measuring time, another mark whose dimensions are as same as the cutting precision is provided. FIG. 2B is another partial enlarged view of the liquid crystal display panel 21, a square mark 24 whose dimensions are as same as the cutting precision is formed on the intersection of the two adjacent cutting lines 22. After completing the cutting of the liquid crystal display panel 21, the cutting precision of the liquid crystal display panel 21 can be checked by visually inspecting distances d3 and d4 between the cutting lines 22 and the square mark 24 or the residue of the square mark 24. When visually inspecting the cutting liquid crystal display panel 21, and find out the distances d3 and d4 are smaller than the dimensions of the square mark 24 or the residue of the square mark 24 is left on the liquid crystal display panel 21, the cutting precision of the liquid crystal display panel 21 is permitted. FIG. 3A is a partial enlarged view of the liquid crystal display panel 21 on which a pattern is formed on the intersection of the adjacent cutting lines 22. Since the pattern 25 covers the square mark 24, the cutting precision of the cut liquid crystal display panel 21 can not be checked. The designing of the square mark 24 is not suitable for the liquid crystal display panel 21 having the pattern on the intersection of the adjacent cutting lines 22. FIG. 3B is a schematic partial plane view of the liquid crystal display panels 21 adjacent to each other and together disposed on a larger substrate. After completing the cutting of the liquid crystal display panels 21a and 21b, whether the distances d3 and d4 between the cutting lines 22 of the liquid crystal display panel 21a and the square mark 24 are larger than the dimensions of the square mark 24 or not can be visually checked. However, it is unreliable to check the cutting precision of the liquid crystal display panel 21b, which is adjacent to the liquid crystal display panel 21a, by visually inspecting the distance d5 between the cutting line 22 of the liquid crystal display panel 21b and the square mark 24. Hence, the designing of the square mark 24 is not suitable for the liquid crystal display panels disposed on the larger substrate adjacent to each other.
Accordingly, it is an intention to provide a mark suitable for various arrangements of the liquid crystal display panels on the large substrate.